John Mayer accused of cheating on ex-girlfriend Katy Perry with actress Kelly Monaco

Singer John Mayer's break-up with ex-girlfriend Katy Perry may be due to the fact that Mayer cheated on Perry with General Hospital star Kelly Monaco.

Star reports that Mayer was secretly seeing Monaco while he was in a relationship with Perry. Reportedly, Monaco and Mayer met each other at a club in Los Angeles a few years ago and instantly bonded with one another. However, the pair were never in a relationship, but still kept in contact with each other, even after Mayer started to date Perry. According to an inside source, "He would text her and try and get her to meet him either at his place in L.A. or a hotel out in the Valley."

E! News exclusively reported that at the end of February, Perry broke up with Mayer. The couple's break-up came as a shock due to the pair being surrounded by rumors of getting engaged. Last November, a source described that the pair were the right match for each other. The source added how, "They are so perfect together."